Hi. Most of the time I just estimate tool height, but for sweeping a taper, it is important to be pretty close to center. At least within 0.01" is desirable. I have one of those screw thread center height gauges for my other lathe, but the idea doesn't work so well after I swapped my tool holder for a large, squat quick change design. There is very little flat area on the top of the compound to measure from. A lip turned at the top of the gauge cannot approach the top of the cutting tool. There are modified square designs which are a little more useful, but at some orientations, the tool holder almost completely obscures the top of the compound, There seems to be no other decent place to measure from. I tried dropping a plate over the ways, suported by the top Vee's. The two are not at equal height, so the plate slopes, as verified by sweeping an indicator connected to the cross slide. I noticed a video by Halligan bridging the two legs of the carriage with a bar, but this does not look level either. It also seems kind of odd, since the top of the carriage is not flat. Many of the import lathes have flat ways, so it is easy to measure these. Would it be appropriate to use a bar with one or two feet on it, so it will register off the flats, or are these not really guaranteed either? Or, get a bar with two little feet on it to contact the flags. I'm not even sure if these are the same height. Another way is to cut a plate with a flat on one end, and a vee notch for the other, and only catch the inside Vee way. One would have to make this plate in a somewhat trial and error way, since there is little online documentation. Does anyone have some good practice/designs?